The number of shootings in the city is sky-rocketing — a worrisome trend that Police Commissioner Bill Bratton blamed on career criminals and increased gang activity at a press conference Monday afternoon.

“It’s career criminals killing and shooting other career criminals,” he said.

Bratton said the gun violence has been concentrated in Upper Manhattan, the central Bronx and northern Brooklyn. The top cop added that more officers will be stationed in these high-crime areas.

In just the past week, shootings increased 66 percent, with 40 occurring between last Monday and this past Sunday. By comparison, there were 24 shootings during the same week in 2014.

The number of shooting victims also rose 76 percent during that time period, with 44 people injured by gunfire compared to 25 for the same period last year.

Shootings are up for the month as well, jumping 33 percent, to 128 incidents, in the past 28 days, sources said. Last year, there were 96 shootings for the same period.

More victims took bullets,too. In the past 28 days, there were 106 shooting victims compared to the 85 at this time last year — a jump of 25 percent.

Crime is down overall, the sources noted. But murders are still up 10 percent year to date, with 109 this year compared with 99 at this time in 2014.

“Warm weather means there are more people on the streets carrying guns, and it is only going to get worse — no matter how many cops you hire — if you don’t back the police,” said a police source.

Sources said police officials are especially trying to deal with the increase in gun violence in neighborhoods north of 59th Street — which includes the Upper West and East Sides, Harlem, Inwood and Washington Heights. The precinct has seen a steady increase in the number of shootings and people shot.

Seven shootings have taken place there in the last week compared to two at the same time last year. The number of shooting victims climbed to nine for the week, compared to two in 2014.

Shooting incidents also are up 71 percent for the month in Manhattan North, with 12 this year vs. seven last year. The number of shooting victims doubled for the same period, with 14 during the last month compared to the seven at this time in 2014.

For the year, shootings are up 54 percent in the north half of the borough, with 37 versus 24 in 2014. Victims are up 84 percent for the same period; 46 versus 25.